The Radiation Oncology Study Center manages the clinical trials for the United States high LET effort which presently consists of five institutions participating in 21 protocols. Four additional facilities will be added during the first year of our new grant and it is projected that 1,000 study patients per year will be accessed. In addition, the Center has initiated joint protocols and a late effect registry with the European high LET Group. Specifically, the Center provides the following services: a. develops and maintains group discipline; b. coordinates protocol development; c. monitors individual study achievements and institutional contributions to the group; d. assures high standards of data; e. coordinates the group quality control program in radiation therapy, medical oncology, surgical oncology and pathology; f. provides liaison with high LET programs throughout the world.